Realizing Anderson localization of surface plasmon polaritons and enhancing their interactions with excitons in disordered nanostructures

Surface plasmon polaritons (SPPs) propagating on metal-dielectric interface suffer from evitable energy losses originated from metals, especially at visible regime, which degrades the quality of SPP-based devices. However, if the size of the devices is sufficiently miniaturized, we can thereby circumvent the problems of large propagation losses. Anderson localization is a possible approach to squeeze SPPs. In this work, we experimentally demonstrate the Anderson localization of SPPs at optical frequencies in both 1D and 2D nanostructures. By increasing the positional disorder of the silver nanoslit arrays and the silver nanohole arrays, strong localization of SPPs appears with an exponentially decreased electric field, the reduced propagation length and the rapid disappearance of the autocorrelation coefficient. Moreover, we manage to enhance the localized SPP-exciton interactions in the 2D disordered silver nanoarrays combined with fluorescent dye molecules. Our study extends Anderson localization of SPPs at visible regime to low-dimensional disordered systems, and provides a unique way to enhance light-matter interaction in SPP-based nanodevices.
References:1) Nano Letters 18, 1896-1902(2018); 2) Appl. Phys. Lett. 116, 201106 (2020); 3) Optics Express 28, 16879-16892 (2020).